In the last decade, considerable research attention has been given to benzimidazole and imidazo[4,5-b and c]-pyridine compounds, particularly those bearing a 2-(trifluoromethyl) group. These compounds, in general, exhibit herbicidal activity; some of the benzimidazole compounds also exhibit insecticidal activity. However, owing to the presence of the trifluoromethyl group, and any electron-withdrawing substitutions son the benzene or pyridine ring, the electrophilic substitution of the benzene or pyridine portion of the ring system has not been feasible. Also, there has hitherto been no technique for the reduction of optimally substituted 1-hydroxy-2-(trifluoromethyl)benzimidazole and 1-hydroxy-2-(trifluoromethyl)imidazo[4,5-b or c]pyridine compounds to the corresponding desoxy compounds.
In the instance of either reduction or introduction of the nucleophilic substituent, the products are useful, in accordance with prior teachings, as herbicides, and, in the case of some of the benzimidazole compounds, as insecticides. See Belgian Pat. Nos. 676,952 and 732,415, regarding benzimidazoles, and U.S. Pat. No. 3,459,759, regarding imidazo[4,5-b or c]pyridines.